Please say this doesn't mean imminent death of my OD unit...
10-07-2009, 11:17 AM
#1
Instructor
Thread Starter
Please say this doesn't mean imminent death of my OD unit...
Driving to work this morning..
Car is still cold and I decide to turn off the OD unit driving through town...
I get on the highway and when I go to turn it back on.... nothing.
By now it's warmed up past the threshold of turning on.
I try twice to put the car in neutral and shut off the car and restart while coasting but to no avail.
I pull off at the next exit and fill up gas hoping a few minutes off will reset something....
When I get back on the highway, it kicks in like it was never gone...
yes- for all of this shifting I was depressing the clutch to minimize any stress...
I'm hoping this is some electrical glitch and not a sign I'll be rebuilding it this winter...
Tj
Car is still cold and I decide to turn off the OD unit driving through town...
I get on the highway and when I go to turn it back on.... nothing.
By now it's warmed up past the threshold of turning on.
I try twice to put the car in neutral and shut off the car and restart while coasting but to no avail.
I pull off at the next exit and fill up gas hoping a few minutes off will reset something....
When I get back on the highway, it kicks in like it was never gone...
yes- for all of this shifting I was depressing the clutch to minimize any stress...
I'm hoping this is some electrical glitch and not a sign I'll be rebuilding it this winter...
Tj
10-07-2009, 11:31 AM
#3
Instructor
Thread Starter
supposedly OK. I didn't have the time to do the stuff myself after i bought it.
Long story short i drove it from MI to NC-OBX the week after i bought it
due to being busy at work i got a reference from a local vette shop on who to have do it for me and had them go through oil, diff fluid( almost empty-probably original), tranny fluid, and OD fluid among other things.
they couldn't replace the OD fluid cause they couldnt get a filter but said they'd at least check the level.
btw- I have to find a source for the filter.... who's everyone been using?
Long story short i drove it from MI to NC-OBX the week after i bought it
due to being busy at work i got a reference from a local vette shop on who to have do it for me and had them go through oil, diff fluid( almost empty-probably original), tranny fluid, and OD fluid among other things.
they couldn't replace the OD fluid cause they couldnt get a filter but said they'd at least check the level.
btw- I have to find a source for the filter.... who's everyone been using?
10-07-2009, 01:22 PM
#4
Le Mans Master
Maybe the switch on the shift **** is just going bad? Did the little overdrive symbol light come on and off when you pressed the button? If not, perhaps it's not a big fix needed.
(I'm going from memory here on my old '87, but I'm pretty sure there was some OD symbol or something when the overdrive unit was engaged)
(I'm going from memory here on my old '87, but I'm pretty sure there was some OD symbol or something when the overdrive unit was engaged)
10-07-2009, 05:30 PM
#5
Racer
Member Since: Oct 2006
Location: Concord, California
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Oh Boy!
Part # for OD unit filter:
CarQuest 85926
AC Delco TF-184
FRAM FT1024
NAPA ATP 14717
Ford D0AZ-7A098-A
Im assuming your talking about a 4+3 OD unit right? If so, check and see if the OD light ever comes on when the OD is on. If it does and you can get in and out of OD with any sort of success, then you probably want to drain/fill your OD unit's tranny fluid. Get the new filter too while they fill it up.
If the OD is still tricky after a refill, then I would suspect its the aging actuator. I just had my 21 year old actuator replaced. The part was like $120 from a random supplier with shipping. It took 1 hour of labor. The shop checked the original actuator with an OHM's meter. It was dead. The new actuator made a world of difference. As soon as you hit the OD button, it engages/disengages instantly-better than ever.
If the actuator isn't the problem, then its the toggle switch on your shifter or console pending what year your Vette is. If its the switch, then its the easiest and cheapest of all fixes.
Good luck!
CarQuest 85926
AC Delco TF-184
FRAM FT1024
NAPA ATP 14717
Ford D0AZ-7A098-A
Im assuming your talking about a 4+3 OD unit right? If so, check and see if the OD light ever comes on when the OD is on. If it does and you can get in and out of OD with any sort of success, then you probably want to drain/fill your OD unit's tranny fluid. Get the new filter too while they fill it up.
If the OD is still tricky after a refill, then I would suspect its the aging actuator. I just had my 21 year old actuator replaced. The part was like $120 from a random supplier with shipping. It took 1 hour of labor. The shop checked the original actuator with an OHM's meter. It was dead. The new actuator made a world of difference. As soon as you hit the OD button, it engages/disengages instantly-better than ever.
If the actuator isn't the problem, then its the toggle switch on your shifter or console pending what year your Vette is. If its the switch, then its the easiest and cheapest of all fixes.
Good luck!
10-07-2009, 08:16 PM
#6
Le Mans Master
Member Since: Aug 2000
Location: Sydney Australia
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I would be checking wiring and O/d relay 1st. Lots of common problems ; bad connections at O/d relay ( early cars lose the insulation off wires ) , bad / loose connection at O/d.
By default the ECM will automatically engage the O/d once up to temp.You have to manualy disengage it as you did.
If it will automatically engage but not manually then the switch is at fault
Last edited by rodj; 10-07-2009 at 08:21 PM.
10-07-2009, 10:42 PM
#7
Team Owner
Member Since: Mar 2001
Location: Cincinnati, Oh USA
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The OD switch is a miniature momentary push button switch, not a toggle switch and its internal return spring is very weak. The weak spring cannot always overcome any rubbing of the rod from the button and when stuck down, your OD will not engage. The shaft going to the switch may not be adjusted for full reliable actuation, check it. Another problem is the hex nut that retains the switch gets loose and the switch then moves down with the actuating rod and won't turn on and thus the OD will not turn on. Check the nut on your switch for tightness.
